Low-Frequency Hydrocarbon Microtremors: Case Studies Around the World

Robert M. Habiger¹, Erik Saenger², and Stefan Schmalholz^2
1Spectraseis, Switzerland
²Geologisches Institut, Switzerland
*[email protected]

A growing number of surveys at different oil and gas fields throughout the world have established the presence of hydrocarbon microtremors with a high degree of correlation to the proven location of these reservoirs. These tremors can be used as a direct hydrocarbon indicator for the optimization of borehole placement during exploration, appraisal and production. The ever-present seismic background noise of the Earth acts as the driving force for the generation of hydrocarbon indicating signals. In contrast to conventional 2-D and 3-D seismic technologies, the investigation of hydrocarbon microtremors may be entirely passive not requiring artificial seismic excitation sources. The results of several surveys over gas and oil fields in different countries are presented. Data were acquired using ultra-sensitive, portable 3-component broadband seismometers with various survey designs. The raw data was processed in multiple steps. Data processing included removing or attenuating signals that are not related to subsurface structures (mainly surface noise generated by road traffic, industrial activities, wind and rain) and correcting the dataset for temporal and near-surface geology-related variations. Finally, maps of different seismic attributes were integrated to form a hydrocarbon potential map. The results are compared with known information of the reservoir (geological model including reservoir depth, drainage area of producing wells and information from borehole measurements). A systematic analysis allows determining reservoir-specific characteristics of hydrocarbon microtremors occurring around the world.

AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain